App Transfer and User Migration - Questions on Apple Sign-In Token Behavior and Testing Process

Hi Apple Developer Community,

We have carefully reviewed the documentation on App Transfer and User Migration, but we still have a few unresolved questions regarding Apple Sign-In token behavior and testing strategies. Would appreciate any guidance!

  1. Token Behavior for Pre-Transfer App Versions

After the app transfer: If a user logs in via an existing pre-transfer version of the app (published under Team A before transfer), will the Apple Sign-In token’s sub (or private email) switch to new value tie to Team B, or unchanged?

This is critical for our user migration plan.

  1. Preserving sub Across Transfers (Internal Team Transfer)

Since our app-transfer is an internal transfer (no change in app ownership outside our organization), is there a way to retain the original sub value(or private email) for users after the transfer?

We are concerned that Apple Sign-In errors during the app transfer process may negatively impact user experience.

  1. Testing the Transfer Process Safely

We’d like to simulate the app transfer and user migration process in a sandbox/test environment before executing it in production. Is there a way to test app transfers without affecting live users? (e.g., a staging mode for transfers)

Thank you for your expertise! Any insights would be invaluable.

App Transfer and User Migration - Questions on Apple Sign-In Token Behavior and Testing Process
 
 
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